WinFS, the evolving Windows File System for Longhorn, will be the core storage subsystem of the next major wave of Microsoft releases. Right? Well, maybe.

This week Microsoft executives opened the door to a possible shift in that strategy at least with respect to Kodiak, the next-generation Exchange Server.

While the plan remains to put Kodiak on the WinFS relational store, business pressures could abrogate that decision, the executives conceded.

While WinFS will incorporate relational technology from the SQL Server world, it must be much simpler, and quality and timing must be right for it to make it into the new Kodiak messaging release. "If we cannot provide that, then the Exchange team has a business to run," said Gordon Mangione, Microsoft's vice president of SQL Server.

Whether WinFS does, in fact, form the basis for Kodiak, boils down to several factors, agreed Tom Rizzo, director of SQL Server product management. "It all depends on timing and business needs. They [the Exchange team] have a business to run and if we don't meet the timeframe and quality they need, if they don't want to build on us, that's fine. Today's plan is to build Kodiak atop the [relational] store, but this is software and human beings. Things happen."

Microsoft has prototypes in house of early Kodiak builds running against the Yukon store now, Rizzo added.

The current Exchange 2003 still runs on a variant of the venerable JET engine. JET stands for Joint Engine Technology.

At some point, it all may come down to semantics. If Microsoft decides to put out an interim release of Exchange between the current Exchange Server 2003 and what is now being called Kodiak, that update could well sit atop yet another modified non-relational store, several observers said. Kodiak has slipped repeatedly along with Yukon itself. At TechEd in June, Microsoft said to expect Kodiak in 2006.

"There will be a service pack release for Exchange 2003, I guarantee that," Rizzo said.

Part of the problem has been mixed messages out of Redmond. Late last month, an Exchange Server marketer told CRN that the decision to go to a relational store for Kodiak was not final.

"If you're going to do a Yukon store for Exchange, you have to make sure we can get there from here. In the past we made the mistake of saying technology could solve everything and said just wait for Yukon and Kodiak. But the store is just one part of many pieces people need. You can save mail to SharePoint. Now we're focused on doing it in JET in Exchange 2003, there is no SQL there and there is no announcement on the next phase," he noted at the time.

A Microsoft spokeswoman in follow up calls said the official had misspoken and the final decision had, in fact, been made. It is unusual for such divergence of opinion on current status to happen so publicly.

Mangione's and Rizzo's comments this week now show there is some wiggle room.

Several Microsoft partners familiar with the issues were not surprised. "Putting Exchange atop a SQL-based store is really, really hard [because] Exchange information is typically unstructured and SQL is structured. Trying to merge the two is no trivial matter," said Andy Sakalian, CEO of Version 3, a Columbia, S.C. solution provider.

As of now, the decision to go with a Yukon-based store stands but with a caveat, said one Microsoft insider who requested anonymity. "Remember Exchange 2003 wasn't planned from the beginning to be on the JET store. It was sort of a forced interim release for Windows 2003 server and Active Directory compatibility." That sort of interim release could happen again, he noted.

Solution providers and company insiders alike said because the Kodiak release remains distant, current Microsoft edicts on product direction are subject to change. There are mandates from corporate on product strategy but individual product groups have their own pressures.

"There are massive dependencies from group to group and yet each group has to hit its own numbers," said one solution provider. "Exchange is trying to grow from an $800 million business to a billion dollar business and is facing pressure of [less expensive] messaging from Oracle and IBM/Lotus. If customers want something, the Exchange group has to provide it [even] if Yukon isn't ready," said one partner source close to the Exchange effort.

Said another partner. "The decision has been made. The war is over. But is it? They say the Civil War is over and yet some people are still fighting it," he said.

One ISV at PDC 2003 last week said he was surprised the Kodiak store is under review but he claims it's a question of when, not if.

"JET is older technology and not nearly as scalable as the current SQL Server 2000 or Yukon, so I'd hope it happens sooner rather than later," said one Microsoft ISV who asked not to be named. "But it will happen. They may change their minds three times before Kodiak ships."